This invention relates generally to an apparatus and method for the detection of underwater vehicular movement, by detecting and distinguishing deviations from a normal surface wave condition caused by interaction and interference with the bow and stern waves artificially generated by a vehicle moving underwater.
Detection of underwater vehicles, such as submarines, has proven to be a most challenging problem in recent years. A variety of approaches to the problem have been tried. It is noted that a vehicle moving on and below the surface of water leaves a wake that is generated by the interaction of the moving vehicle structure and the medium itself. Meteorological conditions above and at the ocean's surface provide a given characteristic surface wave pattern over a large area of the ocean at a time. A vehicle moving underwater generates a wave pattern which is transmitted around the moving vehicle and upon reaching the surface boundary of the medium interferes in a destructive manner with a given surface wave condition, producing a smoothing effect, unless the surface conditions are completely calm, unusual for most parts of the ocean today. Thus in a given overall ocean area, a surface deviation could be noted if one had efficient, accurate means to detect this interference between the natural wave pattern and an artificially interferring wave pattern. Applicant provides an apparatus and method for accomplishing this, thereby allowing one to detect the presence or recent passage of a moving underwater (or surface) vehicle from its wake.